XRCC1 and neoplasm: Objectives of the translational study are the evaluation on tumor samples of markers of treatment efficacy/resistance (i.e. γH2AX, p21/WAF, RAD51, XRCC1, EGFR, p-EGFR, Ki-67) and specific markers of VPA HDAC inhibitory activity (histones and proteins acetylation, Histone deacetylase isoforms) as well as valproate test, histones and proteins acetylation of peripheral blood mononuclear cell, tested on blood samples at baseline and at different time points during treatment.